摘要
采用分子束外延技术,在GaSb衬底上生长了pin结构的InAs(8ML)/GaSb(8ML)超晶格中波红外光电二极管.用阳极硫化和ZnS薄膜对二极管表面进行钝化处理后,二极管漏电流密度降低了三个数量级,零偏阻抗R0达到106Ω,R0A达到103Ωcm2.通过测量电流密度与光敏元周长面积比的关系可知表面漏电不是主要漏电成分;电容电压特性曲线表明吸收层i层背景掺杂浓度约4~5×1014cm-3.在空气中放置一个月后再次测试,发现响应率和探测率几乎没有变化.与化学硫化和SiO2薄膜钝化方法相比,阳极硫化方法是一种更简单和有效的钝化方法.
InAs(8ML)/GaSb(8ML)superlattice with p-i-n structure was grown on GaSb substrates by molecular beam epitaxy.The mid-wavelength infrared photodiodes with different area mesa was fabricated through standard photolithography,wet chemical etching and sputtered metal contacts.The passivation was finished by the anode sulphur technique and sputtered ZnS thin film.Compared with(NH4)2S solution treatment,the surface leackage currents density decreased three orders of magnitude and the R0Aincreased up to 103 times.The zero-bias resistance R0was measured up to 106 ohms.The surface leakage current was not major dark current in photodiodes after the anode sulfur passivation.Capacitance-voltage relation showed that the background concentration in i layer was about 4~5×1014 cm-3.The property of the photodiode appeared no degradation after exposured in air for one month.It verified that anode sulphur passivation is an easy and effective technique.
引文
[1]ROGALSKI A,MARTYNIUK P.Third generation infrared detectors[J].Infrared Physics&Technology,2006,47(3):19-27.
[2]RAZEGHI M,WEI Y,BAE J,et al.Type II InAs/GaSb superlattices for high performance photodiodes and FPAs[C].SPIE,2003,5246:501.
[3]REHM R,WALTHER M.Two-color infrared photodetector using InAsGaSb superlattices[J].Electronics Letters,2006,42(10):10-13.
[4]WU Lei,WANG Tao,WANG Jing.Effect of the LPMOCVD growth parameters for InAs/GaSb superlattices surface morphology[J].Acta Photonica Sinica,2009,38(8):1937-1940.吴学雷,汪韬,王警卫.低压MOCVD生长参量对II型InAs/GaSb超晶格材料表面形貌的影响[J].光子学报,2009,38(8):1937-1940.
[5]ANG Guo,XU Ying,GUO Jie.Growth and characterization of GaSb-based type II InAs/GaSb superlattice photodiodes for mid-infrared detection[J].Chinese Physics Letter,2010,27(7):077305.
[6]PU Ji-chun,CHEN Hui,GUO Jie.Growth and charaterization of InAs/GaSb superlattices photoconductors[J].Acta Photonica Sinica,2008,37(S2):16-18.蒲季春,陈慧娟,郭杰.InAs/GaSb超晶格光导型红外探测器研究[J].光子学报,2008,37(S2):16-18.
[7]WANG Kun-xia,FENG Shi-meng,XU Hua-tian.Influence of Multi-crystalline silicon surfaces passvation on pit topography of textured surface[J].Acta Photonica Sinica,2012,41(2):236-239.王坤霞,冯仕猛,徐华天,等.表面钝化对多晶硅绒面形貌的影响[J].光子学报,2012,41(2):236-239.
[8]ZHU Hui-qun,DING Rui-qin,HU Yi.Hydrogen passivation effecton GaAs thin films[J].Acta Photonica Sinica,2006,35(8):1194-1197.朱慧群,丁瑞钦,胡怡.氢对GaAs薄膜的钝化[J].光子学报,2006,35(8):1194-1197.
[9]PEROTIN M,COUDRAY P,GOUSKOV L,et al.Passivation of GaSb by sulfur treatment[J].Journal of Electronic Materials,1994,23(1):7-11.
[10]FUKUDA Y,SUZUKI Y,SANADA N.(NH4)2S treated InAs surface studied by x-ray photoelectron spectroscopy and low-energy electron diffraction[J].Physics Review B,1997,56(3):1084-1088.
[11]ICHIKAWA S,SUZUKI Y,SANADA N,et al.A(NH4)2S treated InSb surface studied by using x-ray photoelectron spectroscopy,low-energy electron diffraction and inverse photoemission spectroscopy[J].Journal Vacuum Science Technology A,1999,17(2):421-424.
[12]GUO Jie,LIU Ying-kai,PENG Zhen-yu,et al.Sulfur passivation of type II InAs/GaSb superlattice photodiodes[J].Infrared and Laser Engineerin,2011,40(9):217-219.郭杰,刘应开,彭震宇,等.InAs/GaSb超晶格中波光电二极管的硫化研究[J].红外与激光工程,2011,40(9):217-219.
[13]DIETER K.Semiconductor material and device characterization[M].New York:John Wiley&Sons,1990.